lisp/winner.el

   1 ;;; winner.el --- Restore old window configurations
   2
   3 ;; Copyright (C) 1997-1998, 2001-2011 Free Software Foundation. Inc.
   4
   5 ;; Author: Ivar Rummelhoff <ivarru@math.uio.no>
   6 ;; Created: 27 Feb 1997
   7 ;; Keywords: convenience frames
   8
   9 ;; This file is part of GNU Emacs.
  10
  11 ;; GNU Emacs is free software: you can redistribute it and/or modify
  12 ;; it under the terms of the GNU General Public License as published by
  13 ;; the Free Software Foundation, either version 3 of the License, or
  14 ;; (at your option) any later version.
  15
  16 ;; GNU Emacs is distributed in the hope that it will be useful,
  17 ;; but WITHOUT ANY WARRANTY; without even the implied warranty of
  18 ;; MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  19 ;; GNU General Public License for more details.
  20
  21 ;; You should have received a copy of the GNU General Public License
  22 ;; along with GNU Emacs.  If not, see <http://www.gnu.org/licenses/>.
  23
  24 ;;; Commentary:
  25
  26 ;; Winner mode is a global minor mode that records the changes in the
  27 ;; window configuration (i.e. how the frames are partitioned into
  28 ;; windows) so that the changes can be "undone" using the command
  29 ;; `winner-undo'.  By default this one is bound to the key sequence
  30 ;; ctrl-c left.  If you change your mind (while undoing), you can
  31 ;; press ctrl-c right (calling `winner-redo').  Even though it uses
  32 ;; some features of Emacs20.3, winner.el should also work with
  33 ;; Emacs19.34 and XEmacs20, provided that the installed version of
  34 ;; custom is not obsolete.
  35
  36 ;; Winner mode was improved August 1998.
  37 ;; Further improvements February 2002.
  38
  39 ;;; Code:
  40
  41 (eval-when-compile
  42   (require 'cl))
  43
  44
  45 (defmacro winner-active-region ()
  46   (if (boundp 'mark-active)
  47       'mark-active
  48     '(region-active-p)))
  49
  50 (defsetf winner-active-region () (store)
  51   (if (featurep 'xemacs)
  52       `(if ,store (zmacs-activate-region)
  53          (zmacs-deactivate-region))
  54     `(setq mark-active ,store)))
  55
  56 (defalias 'winner-edges
  57   (if (featurep 'xemacs) 'window-pixel-edges 'window-edges))
  58 (defalias 'winner-window-list
  59   (if (featurep 'xemacs)
  60       (lambda () (delq (minibuffer-window) (window-list nil 0)))
  61     (lambda () (window-list nil 0))))
  62
  63 (require 'ring)
  64
  65 (defgroup winner nil
  66   "Restoring window configurations."
  67   :group 'windows)
  68
  69 ;;;###autoload
  70 (defcustom winner-mode nil
  71   "Toggle Winner mode.
  72 Setting this variable directly does not take effect;
  73 use either \\[customize] or the function `winner-mode'."
  74   :set #'(lambda (symbol value) (funcall symbol (or value 0)))
  75   :initialize 'custom-initialize-default
  76   :type    'boolean
  77   :group   'winner
  78   :require 'winner)
  79
  80 (defcustom winner-dont-bind-my-keys nil
  81   "If non-nil: Do not use `winner-mode-map' in Winner mode."
  82   :type  'boolean
  83   :group 'winner)
  84
  85 (defcustom winner-ring-size 200
  86   "Maximum number of stored window configurations per frame."
  87   :type  'integer
  88   :group 'winner)
  89
  90 (defcustom winner-boring-buffers '("*Completions*")
  91   "`winner-undo' will not restore windows displaying any of these buffers.
  92 You may want to include buffer names such as *Help*, *Apropos*,
  93 *Buffer List*, *info* and *Compile-Log*."
  94   :type '(repeat string)
  95   :group 'winner)
  96
  97
  98
  99
 100 \f
 101 ;;;; Saving old configurations (internal variables and subroutines)
 102
 103
 104 ;;; Current configuration
 105
 106 ;; List the windows according to their edges.
 107 (defun winner-sorted-window-list ()
 108   (sort (winner-window-list)
 109         (lambda (x y)
 110           (loop for a in (winner-edges x)
 111                 for b in (winner-edges y)
 112                 while (= a b)
 113                 finally return (< a b)))))
 114
 115 (defun winner-win-data ()
 116   ;; Essential properties of the windows in the selected frame.
 117   (loop for win in (winner-sorted-window-list)
 118         collect (cons (winner-edges win) (window-buffer win))))
 119
 120 ;; This variable is updated with the current window configuration
 121 ;; every time it changes.
 122 (defvar winner-currents nil)
 123
 124 ;; The current configuration (+ the buffers involved).
 125 (defsubst winner-conf ()
 126   (cons (current-window-configuration)
 127         (winner-win-data)))
 128
 129
 130 ;; Save current configuration.
 131 ;; (Called below by `winner-save-old-configurations').
 132 (defun winner-remember ()
 133   (let ((entry (assq (selected-frame) winner-currents)))
 134     (if entry (setcdr entry (winner-conf))
 135       (push (cons (selected-frame) (winner-conf))
 136             winner-currents))))
 137
 138 ;; Consult `winner-currents'.
 139 (defun winner-configuration (&optional frame)
 140   (or (cdr (assq (or frame (selected-frame)) winner-currents))
 141       (letf (((selected-frame) frame))
 142         (winner-conf))))
 143
 144
 145
 146 ;;; Saved configurations
 147
 148 ;; This variable contains the window configuration rings.
 149 ;; The key in this alist is the frame.
 150 (defvar winner-ring-alist nil)
 151
 152 ;; Find the right ring.  If it does not exist, create one.
 153 (defsubst winner-ring (frame)
 154   (or (cdr (assq frame winner-ring-alist))
 155       (let ((ring (make-ring winner-ring-size)))
 156         (ring-insert ring (winner-configuration frame))
 157         (push (cons frame ring) winner-ring-alist)
 158         ring)))
 159
 160 \f
 161 ;; If the same command is called several times in a row,
 162 ;; we only save one window configuration.
 163 (defvar winner-last-command nil)
 164
 165 ;; Frames affected by the previous command.
 166 (defvar winner-last-frames nil)
 167
 168
 169 (defsubst winner-equal (a b)
 170   "Check whether two Winner configurations (as produced by
 171 `winner-conf') are equal."
 172   (equal (cdr a) (cdr b)))
 173
 174
 175 ;; Save the current window configuration, if it has changed.
 176 ;; If so return frame, otherwise return nil.
 177 (defun winner-insert-if-new (frame)
 178   (unless (or (memq frame winner-last-frames)
 179               (eq this-command 'winner-redo))
 180     (let ((conf (winner-configuration frame))
 181           (ring (winner-ring frame)))
 182       (when (and (not (ring-empty-p ring))
 183                  (winner-equal conf (ring-ref ring 0)))
 184         ;; When the previous configuration was very similar,
 185         ;; keep only the latest.
 186         (ring-remove ring 0))
 187       (ring-insert ring conf)
 188       (push frame winner-last-frames)
 189       frame)))
 190
 191
 192
 193 ;;; Hooks
 194
 195 ;; Frames affected by the current command.
 196 (defvar winner-modified-list nil)
 197
 198 ;; Called whenever the window configuration changes
 199 ;; (a `window-configuration-change-hook').
 200 (defun winner-change-fun ()
 201   (unless (or (memq (selected-frame) winner-modified-list)
 202               (/= 0 (minibuffer-depth)))
 203     (push (selected-frame) winner-modified-list)))
 204
 205 ;; A `post-command-hook' for emacsen with
 206 ;; `window-configuration-change-hook'.
 207 (defun winner-save-old-configurations ()
 208   (when (zerop (minibuffer-depth))
 209     (unless (eq this-command winner-last-command)
 210       (setq winner-last-frames nil)
 211       (setq winner-last-command this-command))
 212     (dolist (frame winner-modified-list)
 213       (winner-insert-if-new frame))
 214     (setq winner-modified-list nil)
 215     (winner-remember)))
 216
 217 ;; A `minibuffer-setup-hook'.
 218 (defun winner-save-unconditionally ()
 219   (unless (eq this-command winner-last-command)
 220     (setq winner-last-frames nil)
 221     (setq winner-last-command this-command))
 222   (winner-insert-if-new (selected-frame))
 223   (winner-remember))
 224
 225 ;; A `post-command-hook' for other emacsen.
 226 ;; Also called by `winner-undo' before "undoing".
 227 (defun winner-save-conditionally ()
 228   (when (zerop (minibuffer-depth))
 229     (winner-save-unconditionally)))
 230
 231
 232
 233 \f
 234 ;;;; Restoring configurations
 235
 236 ;; Works almost as `set-window-configuration',
 237 ;; but does not change the contents or the size of the minibuffer,
 238 ;; and tries to preserve the selected window.
 239 (defun winner-set-conf (winconf)
 240   (let* ((miniwin  (minibuffer-window))
 241          (chosen   (selected-window))
 242          (minisize (window-height miniwin)))
 243     (letf (((window-buffer miniwin))
 244            ((window-point  miniwin)))
 245       (set-window-configuration winconf))
 246     (cond
 247      ((window-live-p chosen) (select-window chosen))
 248      ((window-minibuffer-p (selected-window))
 249       (other-window 1)))
 250     (when (/= minisize (window-height miniwin))
 251       (letf (((selected-window) miniwin) )
 252         (setf (window-height) minisize)))))
 253
 254
 255
 256 (defvar winner-point-alist nil)
 257 ;; `set-window-configuration' restores old points and marks.  This is
 258 ;; not what we want, so we make a list of the "real" (i.e. new) points
 259 ;; and marks before undoing window configurations.
 260 ;;
 261 ;; Format of entries: (buffer (mark . mark-active) (window . point) ..)
 262
 263 (defun winner-make-point-alist ()
 264   (letf (((current-buffer)))
 265     (loop with alist
 266           for win in (winner-window-list)
 267           for entry =
 268           (or (assq (window-buffer win) alist)
 269               (car (push (list (set-buffer (window-buffer win))
 270                                (cons (mark t) (winner-active-region)))
 271                          alist)))
 272           do (push (cons win (window-point win))
 273                    (cddr entry))
 274           finally return alist)))
 275
 276 (defun winner-get-point (buf win)
 277   ;; Consult (and possibly extend) `winner-point-alist'.
 278   ;; Returns nil if buf no longer exists.
 279   (when (buffer-name buf)
 280     (let ((entry (assq buf winner-point-alist)))
 281       (cond
 282        (entry
 283         (or (cdr (assq win (cddr entry)))
 284             (cdr (assq nil (cddr entry)))
 285             (letf (((current-buffer) buf))
 286               (push (cons nil (point)) (cddr entry))
 287               (point))))
 288        (t (letf (((current-buffer) buf))
 289             (push (list buf
 290                         (cons (mark t) (winner-active-region))
 291                         (cons nil (point)))
 292                   winner-point-alist)
 293             (point)))))))
 294
 295 \f
 296 ;; Make sure point does not end up in the minibuffer and delete
 297 ;; windows displaying dead or boring buffers
 298 ;; (c.f. `winner-boring-buffers').  Return nil if all the windows
 299 ;; should be deleted.  Preserve correct points and marks.
 300 (defun winner-set (conf)
 301   ;; For the format of `conf', see `winner-conf'.
 302   (let* ((buffers nil)
 303          (alive
 304           ;; Possibly update `winner-point-alist'
 305           (loop for buf in (mapcar 'cdr (cdr conf))
 306                 for pos = (winner-get-point buf nil)
 307                 if (and pos (not (memq buf buffers)))
 308                 do (push buf buffers)
 309                 collect pos)))
 310     (winner-set-conf (car conf))
 311     (let (xwins)                        ; to be deleted
 312
 313       ;; Restore points
 314       (dolist (win (winner-sorted-window-list))
 315         (unless (and (pop alive)
 316                      (setf (window-point win)
 317                            (winner-get-point (window-buffer win) win))
 318                      (not (member (buffer-name (window-buffer win))
 319                                   winner-boring-buffers)))
 320           (push win xwins)))            ; delete this window
 321
 322       ;; Restore marks
 323       (letf (((current-buffer)))
 324         (loop for buf in buffers
 325               for entry = (cadr (assq buf winner-point-alist))
 326               do (progn (set-buffer buf)
 327                         (set-mark (car entry))
 328                         (setf (winner-active-region) (cdr entry)))))
 329       ;; Delete windows, whose buffers are dead or boring.
 330       ;; Return t if this is still a possible configuration.
 331       (or (null xwins)
 332           (progn
 333             (mapc 'delete-window (cdr xwins)) ; delete all but one
 334             (unless (one-window-p t)
 335               (delete-window (car xwins))
 336               t))))))
 337
 338
 339
 340 ;;;; Winner mode  (a minor mode)
 341
 342 (defcustom winner-mode-hook nil
 343   "Functions to run whenever Winner mode is turned on."
 344   :type 'hook
 345   :group 'winner)
 346
 347 (defcustom winner-mode-leave-hook nil
 348   "Functions to run whenever Winner mode is turned off."
 349   :type 'hook
 350   :group 'winner)
 351
 352 (defvar winner-mode-map
 353   (let ((map (make-sparse-keymap)))
 354     (define-key map [(control c) left] 'winner-undo)
 355     (define-key map [(control c) right] 'winner-redo)
 356     map)
 357   "Keymap for Winner mode.")
 358
 359 ;; Check if `window-configuration-change-hook' is working.
 360 (defun winner-hook-installed-p ()
 361   (save-window-excursion
 362     (let ((winner-var nil)
 363           (window-configuration-change-hook
 364            '((lambda () (setq winner-var t)))))
 365       (split-window)
 366       winner-var)))
 367
 368 \f
 369 ;;;###autoload
 370 (defun winner-mode (&optional arg)
 371   "Toggle Winner mode.
 372 With arg, turn Winner mode on if and only if arg is positive."
 373   (interactive "P")
 374   (let ((on-p (if arg (> (prefix-numeric-value arg) 0)
 375                 (not winner-mode))))
 376     (cond
 377      ;; Turn mode on
 378      (on-p
 379       (setq winner-mode t)
 380       (cond
 381        ((winner-hook-installed-p)
 382         (add-hook 'window-configuration-change-hook 'winner-change-fun)
 383       (add-hook 'post-command-hook 'winner-save-old-configurations))
 384        (t (add-hook 'post-command-hook 'winner-save-conditionally)))
 385       (add-hook 'minibuffer-setup-hook 'winner-save-unconditionally)
 386       (setq winner-modified-list (frame-list))
 387       (winner-save-old-configurations)
 388       (run-hooks 'winner-mode-hook)
 389       (when (called-interactively-p 'interactive)
 390         (message "Winner mode enabled")))
 391      ;; Turn mode off
 392      (winner-mode
 393       (setq winner-mode nil)
 394       (remove-hook 'window-configuration-change-hook 'winner-change-fun)
 395       (remove-hook 'post-command-hook 'winner-save-old-configurations)
 396       (remove-hook 'post-command-hook 'winner-save-conditionally)
 397       (remove-hook 'minibuffer-setup-hook 'winner-save-unconditionally)
 398       (run-hooks 'winner-mode-leave-hook)
 399       (when (called-interactively-p 'interactive)
 400         (message "Winner mode disabled"))))))
 401
 402 ;; Inspired by undo (simple.el)
 403
 404 (defvar winner-undo-frame nil)
 405
 406 (defvar winner-pending-undo-ring nil
 407   "The ring currently used by `winner-undo'.")
 408 (defvar winner-undo-counter nil)
 409 (defvar winner-undone-data  nil) ; There confs have been passed.
 410
 411 (defun winner-undo ()
 412   "Switch back to an earlier window configuration saved by Winner mode.
 413 In other words, \"undo\" changes in window configuration."
 414   (interactive)
 415   (cond
 416    ((not winner-mode) (error "Winner mode is turned off"))
 417    (t (unless (and (eq last-command 'winner-undo)
 418                    (eq winner-undo-frame (selected-frame)))
 419         (winner-save-conditionally)     ; current configuration->stack
 420         (setq winner-undo-frame (selected-frame))
 421         (setq winner-point-alist (winner-make-point-alist))
 422         (setq winner-pending-undo-ring (winner-ring (selected-frame)))
 423         (setq winner-undo-counter 0)
 424         (setq winner-undone-data (list (winner-win-data))))
 425       (incf winner-undo-counter)        ; starting at 1
 426       (when (and (winner-undo-this)
 427                  (not (window-minibuffer-p (selected-window))))
 428         (message "Winner undo (%d / %d)"
 429                  winner-undo-counter
 430                  (1- (ring-length winner-pending-undo-ring)))))))
 431
 432
 433
 434 \f
 435 (defun winner-undo-this ()              ; The heart of winner undo.
 436   (loop
 437    (cond
 438     ((>= winner-undo-counter (ring-length winner-pending-undo-ring))
 439      (message "No further window configuration undo information")
 440      (return nil))
 441
 442     ((and                               ; If possible configuration
 443       (winner-set (ring-ref winner-pending-undo-ring
 444                             winner-undo-counter))
 445                                         ; .. and new configuration
 446       (let ((data (winner-win-data)))
 447         (and (not (member data winner-undone-data))
 448              (push data winner-undone-data))))
 449      (return t))                        ; .. then everything is fine.
 450     (t ;; Otherwise, discharge it (and try the next one).
 451      (ring-remove winner-pending-undo-ring winner-undo-counter)))))
 452
 453
 454 (defun winner-redo ()                   ; If you change your mind.
 455   "Restore a more recent window configuration saved by Winner mode."
 456   (interactive)
 457   (cond
 458    ((eq last-command 'winner-undo)
 459     (winner-set
 460      (if (zerop (minibuffer-depth))
 461          (ring-remove winner-pending-undo-ring 0)
 462        (ring-ref winner-pending-undo-ring 0)))
 463     (unless (eq (selected-window) (minibuffer-window))
 464       (message "Winner undid undo")))
 465    (t (error "Previous command was not a `winner-undo'"))))
 466
 467 ;;; To be evaluated when the package is loaded:
 468
 469 (unless (or (assq 'winner-mode minor-mode-map-alist)
 470             winner-dont-bind-my-keys)
 471   (push (cons 'winner-mode winner-mode-map)
 472         minor-mode-map-alist))
 473
 474 (provide 'winner)
 475 ;;; winner.el ends here